Taxonomy: When Carl von Linné (more commonly known as Carl Linnaeus
prior to his ennoblement in 1761) included the European badger in the
10th volume of his Systema naturae per regna tria naturae, secundum
classes, ordines, genera, species, cum characteribus differentiis,
synonymis, locis (understandably shortened to System naturae by most),
he placed it in the Ursidae family alongside the bears (as Ursus meles). Over the years, subsequent authors have moved the badger into the
Meles
genus (as proposed by the French zoologist Mathurin Jacques Brisson in
his 1762 Regnum animale in classes IX). Today, all badgers are part of
the Mustellidae (Weasel Family), which is the largest and most diverse
family within the Carnivore order. Globally there are 66 extant mustelid
species, divided into 25 genera and six subfamilies; representatives of
the Musteliidae include the Otters, Skunks, Weasels, Stoats and Badgers. Worldwide, we currently recognize nine species of badger, divided into
seven genera: Arctonyx, Suillotaxus, Mydaus,
Melogale, Mellivora,
Taxidea and Meles. The only badger found wild throughout the UK and
Europe is Meles meles. Owing to terrific geographical variation, many
subspecies of Meles meles have been proposed. Early species revisions by
N Bobrinskii et al. have suggested that at least 10 of the 40-or-so
proposed subspecies can be grouped into four main ones: Meles meles
meles
(widely distributed across Europe), Meles meles canescens
(Transcaucasia), Meles meles leptorhynchus (south-east Russia and
Siberia) and Meles meles amurensis (Manchuria). Subsequent
authors have, however, been less sure of these groupings and it seems
that everyone has their own ideas on which are and which are not valid.

In their 1961 Checklist of Palaearctic and Indian Mammals, John Ellerman and Terence Morrison-Scott list 23 subspecies, while in his
Mammals of the Palaearctic Region, Gordon Corbet lists 39. At least part
of the problem is that many of these proposed subspecies are based on
rather minor differentiation in dental, skeletal and 'mask'
characteristics and in their 1996 book Badgers, Ernest Neal and Chris Cheeseman argue that these are perhaps better looked upon as "races"
rather than true subspecies. The variation seen amongst certain
'subspecies' is, however, sufficient to make some authors argue that there may be
as many as three species within the Meles genus and more recent studies
seem to bear this out. Mitochondrial DNA (i.e. that inherited through
the maternal line) data obtained by Naoko Kurose and his colleagues at
Hokkaido University in Japan suggest that, at the very least, Eurasian
badgers should be divided into European and Asian forms. The DNA
evidence, coupled with recent studies by Russian zoologists Gennady
Baryshnikov and Alexi Abramov -- on baculum morphometrics, fur
colouration, skull morphology and dentition differentiation -- highlight
the need for an overhaul of the current thinking of Meles
phylogeny. (Photo: Badgers are part of the
Mustelid family, along with well-known species such as the stoat,
European otter and the controversial American mink, Neovision vision, pictured here).

In a 2003 paper to the Russian Journal of Theriology, a group of
scientists from the Russian Academy of Science analysed cheek teeth
variability in the Eurasian badger and were able to make some putative
conclusions on badger taxonomy. The cheek teeth are the molars and
premolars of mammals that are used in the mastication (i.e. grinding) of
food. The cheek teeth of mammals tend to be highly complex in structure
and because they are typically so highly adapted to specific tasks, they
are commonly used in phylogenetic studies. After studying the cheek
teeth in 661 skulls sequestered from 11 museums from across the globe,
Baryshnikov and his colleagues found two obvious geographic groups (east
and west), which they argue are distinct species. If we take the results
of Baryshnikov et al. and fellow Russian scientists Alexi Abramov and
Andrey Puzachenko (who have done much work on untangling badger
phylogeny through variations in hard tissue morphology), it seems that
we can assign the western (European) group as Meles meles, the eastern
(Japanese) group as Meles anakuma, a Far Eastern (Asian) group as
Meles
leucrus and also acknowledge the existence of a new subspecies (Meles
meles milleri) from the far south-west of Norway. Additional studies on
the skull and dental characteristics of the western group suggest that
it can be further divided into two distinct forms (probably subspecies):
the European badger proper (presumably Meles meles meles), which
inhabits most of Europe and the Caucasus-Pamir badger (probably Meles
meles canescens) found from Transcaucasia (the transitional region
between Europe and Asia) to the Pamir-Alai Mountains in central Asia.

Recent work on the mitochondrial DNA of the mustelids by a
multinational team of scientists largely supports the Russian study,
although their data suggest that the Eurasian badger can be divided into
four distinct phylogenetic groups: Europe, Southwest Asia, North and
East Asia and Japan. In this paper -- published in Molecular Ecology -- Josep Marmi at the Universitat Autonoma de Barcelon (Spain) and
colleagues write that the first three of the aforementioned groups has
evolved separately since the end of the Pliocene (some 2.4 million years
ago), while the Japanese badgers separated from the continental Asian
ones during the middle Pleistocene (781,000 to 126,000 years ago). In
their study, Baryshnikov et al. speculate that the ancestor of the
Eurasian badger was Meles thorali, which had a Palaearctic
distribution during the late Pliocene (about 3.6 to 1.8 million years
ago).

Similar studies by other authors suggest that the Melinae subfamily
requires some re-arranging -- including the removal of the American
badger (Taxidea taxus) into its own monotypic subfamily (Taxidiinae) and
the assigning of the Arctonyx to the Meles genus -- and predict the
existence of three subspecies of Meles meles.

Suffice to say, there is still much in the way of nomenclatural dust
that has yet to settle. While the recent work with mtDNA, cranial
morphometrics and dentition has made considerable headway in clarifying
the taxonomic interrelationships of badgers, there is still a need for
more data on the subject, especially with a view to assessing the
validity of Meles subspecific taxonomy. For the purposes of this
article, I consider Meles meles meles as the type species of European
badger found throughout Western Europe. Pending further evidence to the
contrary, I follow other authors in placing the Eurasian badger within
the Melinae -- not to be confused with the Mellinae, which is a
well-established subfamily ascribed to the hymenopteran digger wasps
(Mellinus) -- a subfamily of the Mustelidae. Consequently, the basic
taxonomic hierarchy for the European badger is as follows:

Weight: Weight varies according to season, with adults usually
between 6 and 7 kg (13 – 15 lbs) in summer and 12 to 14 kg (26 – 31 lbs)
in winter. The average adult weight in the autumn is about 12kg, while
that for spring is circa 9kg (20 lbs). (Back to Menu)

Colour: Typically, mature badgers have a silvery-grey to black body
and tail, with a paler stomach (the white abdominal fur being very thin)
and dark paws. Badgers are easily identified by their characteristic
black-and-white striped face (mask) and white margins to their ears.
Variations to this colour scheme, although rare, include white
(including albino and semi-albino), melanistic (very dark) and
erythristic (ginger-brown and ginger-red -
left) badgers. The pelage has three
phases correlated with the moult phase: a thick winter coat, thinner
summer coat and a light autumn coat. There is a single moult each year,
beginning in the spring with shedding of the underfur and guard hairs,
which proceeds from the back of the neck and shoulders backwards to the
flanks; summer heralds pelage re-growth, beginning with the guard hairs
followed by the underfur, proceeding back-to-front. The new coat is
complete by the autumn. (Back to Menu)

Distribution: Badgers live in most of Europe, excluding northern
Scandinavia, Iceland, Corsica, Sardinia and Sicily. They can also be
found in parts of Asia, as far east as China. In the UK, badgers are
most common in the south and west, being noticeably scarcer in the urban
Midlands, parts of Scotland and parts of East Anglia. Some badgers
inhabit urban areas, especially along the South coast of the UK, Essex,
London, Bath and Bristol. Ireland represents the western limit of their
range and badger populations in mainland Britain and Ireland seem to
constitute two geographically-distinct populations; populations across
Europe and the British Isles as a whole are morphologically and
generally distinct. Badgers are also found on the Isle of Wight
(although we have hardly any data on population sizes here). The Shropshire Badger Group estimates that there are currently 43,000 badger
clans in the UK. (Back to Menu)

Longevity: Ageing of badgers is something of an acquired skill and is
often based upon craniometric (i.e. skull) measurements. A
paper in 1993 by biologists at the University College in Dublin suggests,
however,
that such measurements have insufficient reliability to accurately age
badgers more than three years old (at which point the skull growth is
complete). Instead, the scientists recommend that, for adult badgers,
annuli in cementum (i.e. the dental equivalent to counting the rings of
a tree stump) should be considered instead. Unfortunately, even the use
of cementum annuli is not the universal answer, because their deposition
is far from geographically catholic. Although this technique has proved
quite successful for ageing badgers in Sweden, it is far less reliable
for ageing individuals from the southwest of England. The longevity
record for Eurasian badgers in the wild is fifteen years, while captive
specimens have survived for nearly twenty. The average age to which
badgers live to is two years (because of a high cub mortality) and only
around 1% will live to be teenagers. Assuming a badger lives past the
age of two (of which around 50% do), it may live for seven or eight
years. The main cause of death in adult badgers is starvation (old
badgers often have black, decayed and warn-down teeth), while the high
juvenile mortality is often a result of parasitic load. (Back to Menu)

Sexing: Sexing badgers is not an easy task because
there is remarkably little sexual dimorphism in this species (i.e. the
males and females look very similar). Outside of the breeding season --
during which sexing can often be made on the basis of testes descent,
lactation (i.e. highly visible teats) or cub association -- it is
sometimes possible to separate males and females because the male is
often (but certainly not always) bigger than the female, with a broader
head, fuller cheeks and a less tufted tail. On a more intimate level,
studies on the variation in skull morphology by Russian Academy of
Science biologists have revealed that some craniological characteristics
show dimorphism between the sexes. Of these features, it seems that
although variation was found in the overall skull size, the lower jaw
(mandible) and molars, the most stable characteristic is the length (and
to a lesser extent, the width) of the upper canines, which are larger in
males than females. Given the spread of their data, however, I remain
unconvinced that canine size is a fool-proof method of sexing a badger,
although sexing a badger skull using their data as a whole is perhaps
more reliable. Moreover, work by the WildCRU team at Oxford University
on the badgers in Wytham Woods has found that the average variation in
skull size between the sexes is of the order of half-a-millimetre!
According to the Devon Badger Group (see Links), the only way to be sure
is to roll it over! Males are referred to as boars, while females are
called sows. (Back to Menu)

Activity: Badgers are primarily nocturnal (with some crepuscular
tendencies) because their prey (earthworms throughout most of their
range) only comes to the surface at night to breed. Generally, here in
the UK, badgers emerge from their setts before dusk between May and
August and after dark for the rest of the year; they are also less
active from November to February – they tend to remain at the sett for
about an hour before moving away to forage. Although badgers do not
hibernate (see Q/A), in some parts of their range they may enter
states of torpor during very cold or snowy periods – during torpor, the
badgers will remain in the sett (often for several weeks) and metabolise
fat reserves accumulated during the summer and autumn. There is usually
a marked decrease in a badger's body temperature during the winter and
early spring, with the body temperature between 2 deg-C and 9 deg-C (3.6 –
16.2 deg-F) lower from November to April than during the late spring. This
decrease in body temperature allows for greater economy of fat reserves
at a time when food is typically scarce or buried under snow. Indeed,
this probably explains why studies have found that breeding sows may
have three times the drop in body temperature of non-breeding
individuals. In the American badger (Taxidea taxus), the
same 9oC slump in body temperature is accompanied by a pronounced
decrease (sometimes of more than 50%) in heart rate. During periods of
exceptionally cold weather, badgers will often use a latrine inside the
sett, rather than venturing outside. While activity is sporadic and
unpredictable through the winter months, badgers may be seen out
foraging during the winter, even in the snow! Post-winter emergence is
generally late-February or early March and by mid-summer, badgers often
spend time away from the sett during the day, even sleeping out in deep
bedding piles. In more remote locations, cubs may be seen playing
outside during daylight.

Season has a profound impact on the ranging of badgers in the UK. A
study by the University of Sussex found radio-collared badgers had
largest ranges during the summer and autumn, with clan range declining
during the winter months. A similar study published in the Journal of
Animal Ecology during 2002 found that dominant female and
subordinate badgers used only a small fraction of their territories,
moved short distances at low speed and covered small areas each night
during the winter and spring. Males were observed to use the same
proportion of their territories throughout the year, although they moved
faster, over longer distances and covered greater areas per period of
activity during the winter than females. As food availability
(i.e. young rabbits, in this study) increased in the autumn, so did body
condition, although range was reduced (presumably a reflection of the
fact that the badgers didn’t need to move so far to find food).

A study published in the Journal of Biogeography found that the
activity patterns of European badgers in Poland’s Bialowieza Primeval
Forest and other Palaearctic (from western Europe to Central Siberia)
populations differed between spring and autumn and between adult and
subadult individuals. On average, badgers were seen to emerge from setts
at 19:00 and return to them at 03:42, with the highest activity seen
between 20:00 and 03:00. The duration of activity was dependent on daily
temperature and the badgers were inactive for an average of 96 days
(about 3 months) each year. The study also found that in regions with
warm climates, badgers were active throughout the year, with change in
overall body mass; in areas with bitter winters badgers increased their
body mass two-fold from spring to autumn, and underwent torpor for as
long as six months. The conclusion of the paper was that the primary
factor regulating these differences was a winter shortage of earthworms.
A similar study published in the journal Mammalia during 2005 reports on
the activity rhythms and movement patterns of badgers in cork-oak
woodland of southwest Portugal. The research (carried out by Luis Rosalino and Margarida Santos-Reis at the Universidare de Lisboa
in Portugal in collaboration with Oxford University's David Macdonald)
found that badgers typically emerged from the sett just after sunset and
returned before sunrise; overall, the badgers were active for an average
of just over eight hours and travelled an average of just under 4km (3
miles) per night. The biologists also report that there was no
significant reduction in activity during the winter months and that
these badgers showed a much lower site fidelity than their northern
conspecifics; an observation that may be explained by larger territory
sizes in Mediterranean habitats.

The phase of the moon has been suggested to play an important role in
regulating badger activity. The moon has long been thought to have a
profound impact on the lives of plants and animals; as long ago as the
first century AD, the Roman natural philosopher Pliny (Gaius Plinius
Secundus) advised farmers to pick fruit for market before the full moon,
when it was at its best. There are, of course, also the suggestions that
lunar cycles can be linked with changes in human behaviour and even
fertility; the word "lunacy" comes from the Latin "luna", meaning moon.
Unfortunately, the data simply do not exist to scientifically validate
such hypotheses at the moment. Data-wise, the situation for non-humans
is a little different and several studies have demonstrated the
pronounced impact that the moon can have on some animals (especially
fish and marine invertebrates) and plants (perhaps most notably certain
vegetables). In the case of the badger, opinions are mixed. In their
aforementioned Polish study, Rosalino and his colleagues found no
evidence that moonlight had any significant impact on badger activity.
Nonetheless, in a fascinating (yet, it has to be said, heavily anecdotal)
contribution to September 2005's BBC Wildlife Magazine, Plymouth Marine
Laboratory hydrothermal vent biologist David Dixon presented his
observations on badger activity and lunar phases. Dr Dixon reports that
dominant individuals in his study group of badgers in Plymouth (UK)
scent-marked more often, mated more frequently (and for longer periods)
and were more aggressive towards each other when the moon was new (and
consequently with nights at their darkest, because the illuminated face
of the moon was facing away from the earth) than when it was full (i.e.
with nights at their lightest). The actual mating events that Dixon
recorded were clustered within the moon's last quarter (i.e. the lunar
'dark phase', when only the left half of the moon is visible), implying
that reproductive behaviour in badgers may be strongly influenced by the
moon. Dr Dixon suggests that mating during the darkest nights may
reduce the risk of being noticed by a potential predator, especially
given that mating durations may exceed an hour. On reflection this seems
rather unlikely given that the Eurasian badger has no natural predators
(only competitors in the shape of foxes and bears). Similarly, despite
studying the behaviour of Wytham’s badgers for many years, Oxford’s
WildCRU team (principally Drs Christina Buesching and Chris Newman) have
yet to find any evidence for lunar-mediated activity variation.

While badgers obviously have their own 'built in' activity rhythms,
these patterns can be altered by human interference. A paper by a group
of scientists fronted by Frank Tuyttens, now at the Agricultural
Research Centre in Belgium, reported that anthropogenic (human-induced)
control of badgers changed their natural circadian (daily) rhythm. Using
infra-red video cameras, the researchers were able to demonstrate that
badgers in a population subjected to lethal control by humans, emerged
from their setts later in the evening than those from a nearby,
undisturbed population. Indeed, it appears that human disturbance may
have more wide-ranging consequences for badger populations than we
previously realised. Several studies on the effectiveness of lethal
control on badgers and whether it was effective at stamping out Bovine
TB suggests that the more disturbed a sett becomes, the more unstable
the population gets – thus highly disturbed setts are likely to
encourage badgers to leave the main sett in search of undisturbed
pastures. This may actually serve to increase the spread of TB! See
Badgers and TB for more info on this subject. (Back to Menu)

Setts: A badger’s homestead is referred to as a sett. Reflecting the
dwelling of what is -- in parts of its range -- a highly social mammal,
badger setts are large and spacious enough to accommodate as many as 35
animals (in the largest naturally supported clan ever recorded in Woodchester Park during 1989), although between six and eight
individuals is more common. Setts are generally constructed on sloping
ground in woodland or on the periphery of farmland, although they have
been found in scrub, natural caves, tips, under buildings, in
embankments, quarries, hedgerows and sea cliffs. In the UK, badgers seem
to show a preference for deciduous woodland and copses (56% of setts),
with fewer setts (13%) found in hedgerows and scrub and even fewer (9%)
in open fields. Similarly, a study in the Republic of Ireland (RoI)
published in 1993 reports that 43% of setts were in hedgerows or tree
lines, 19% in woodland and 21% in scrub. The same paper found that the
average sett density was similar in the RoI to that on the UK mainland,
with roughly two setts per square-kilometre. (Photo:
Badger dens (called "Setts") are usually characterised by a large spoil
heap of soil and discarded bedding outside each main entrance.)

A large sett may consist of up to 100 m (330 ft) of tunnels, with as
many as 40 entrances/exits, each about 30 cm (12 inches) in diameter.
Here in the UK, a study found an established sett in the Cotswolds with
twelve entrances and tunnels totaling more than 300 metres (1000 ft);
the study estimated that the badgers had moved 25 tonnes (55,000 lbs) of
soil to create the network. In his book Badgers, Mammal Society chairman
Michael Clark describes the internal architecture of a sett. Clark notes
that the sleeping quarters are more like extensions off the tunnels than
'rooms' per se and these chambers contain bedding (in the form of dried
grass and leaves), which provides vital insulation of the chamber during
the winter - in one particular experiment, Clark discovered that bedding
may stay underground for as long as 14 months, before it is replaced.
Clark also writes that dung is often found in discrete corners of the
sett complex, although not to the extent seen in the dens of -- or parts
of the sett used by -- foxes. The entrances may lead back into random
blind tunnels and a maze of interlinking routes between bedding chambers
is generally found. Around the edge of the sett's main entrance is a
mound of highly compacted earth and, in many instances, discarded
bedding material. The sett system often consists of a primary and
several 'secondary' setts spread around the territory. During her Ph.D
thesis at the University of Exeter, Penny Thornton classified these
setts into four groups, based on their frequency of use and topography.
Dr Thornton's scheme classifies setts as follows:

SETT TYPE

DISTINGUISHING CHARACTERISTICS

Main Sett

Many entrances (both used and disused),
large spoil heap and well-worn paths. One main sett per clan.

Annex Sett

May also have well-used entrances with numerous paths to the
main sett, which is typically 50 to 150m (164 - 492 ft) away.

Subsidiary Sett

Variable number of entrances. Only some entrances connect to
the main sett by obvious paths.

Outlier Sett

One or two entrance holes and no well defined pathways to
the main sett. Used sporadically.

In the main sett, there are usually chambers on a number of levels.
The main nesting chamber is often between five and ten metres (16.5 –
33 ft) from the tunnel entrance and about three metres (10 ft) below the
surface. The chambers are lined with dry vegetation that is regularly
changed - during the later winter and early spring it is common for
badgers to drag the bedding outside to 'air' it out. Clans may dig a new
chamber for each successive brood of cubs and setts may be inhabited by
several generations of badger. In one particular case, a sett was
inhabited by the same family of badgers for more than 200 years. This
sett extension by successive clans may partially explain why badgers are
often very reluctant to leave well-established setts. In very cold
regions, the main sett is dug below the level at which the ground
freezes and all members of the clan will sleep in the same chamber – it
is probable that sleeping together helps ‘share’ body heat.
Additionally, -- and because of a lack of air circulation within the
sett -- ventilation holes are observed in some setts. Such holes are
typically about 4cm (1.5 inches) in diameter and extend from the
ground's surface to a tunnel directly below. Studies by Tim Roper at
Sussex University suggest that in the deepest parts of the sett, it is
only movement of the badgers themselves that engenders airflow.

A group study at the University of Sussex, this time published in
Behaviour looked at sett use in European badger populations. They found
that subsidiary and outlier setts were used mainly during the summer
and, although usage was not related to sex or body condition, outliers
tended to be used by younger animals and had a larger number of fleas
than the main sett. The biologists also recorded that the main sett was
not divided into separate interior territories. A study by Jacek
Goszczynski and a colleague at the Polish Department of Forest
Protection and Ecology found that badgers had two peaks of sett use: one
in April and another in August – September. The Polish biologists
observed that the same setts were visited by foxes and badgers, which
tallies with previous observations by Ernest Neal that various species
-- including woodmice, bank voles, brown rats, rabbits, weasels and cats
(feral and wild) -- may 'share' setts with badgers. Although foxes may
share setts with (and even raise their cubs in setts occupied by)
badgers, it is generally considered that the faeces, urine and food
remains that have frequently been found in fox dens are odious to
badgers, which will often move to another sett if they aren't breeding.

A study conducted by biologists Rafal Kowalczyk, Andrzej Zalewski and
Bogumila Jedrejewska of the Polish Academy of Sciences' Mammal Research
Unit in Poland's Bialowieza Primeval Forest found that, in addition to
various setts throughout the territory, these badgers used a number of
shelters. In this low-density population (about two individuals per
10 sq-km), the badgers used several setts and daily shelters (particularly
tree hollows) to save energy while moving about their large territories
(either foraging or exploring). An interesting finding of this study was
that setts may play a role in marking the sites and, while the number of
setts being used by the badgers at any given time increased with
increasing territory size, sett density (that is to say, the number of
setts per square kilometre) did not. Subsequently, the zoologists
speculate that sett utilization in high- and low-density badger
populations are regulated by different factors. In high-density
populations, social factors (i.e. large group size, intraclan
aggression, parasites etc.) force badgers to use multiple setts, while
the increased food availability that permits clan formation in the first
place allows more time and energy to be spent digging new and modifying
existing setts. Conversely, in low-density populations, food is at
considerably more of a premium and more time and energy must be spent
looking for it (thus less can be spent modifying the sett); making use
of natural shelters allows the badgers to cover a larger area more
efficiently when foraging. (Photo: Discarded
bedding outside a badger sett.)

Some interesting work has been done looking at whether the
distribution of badger setts can be associated with specific biological
features. One paper (published in the Journal of Natural History back in
1997) by zoologists at the University College Cork in Ireland reports on
an interesting association between badger sett location and the common
woodland fungus Phallus impudicus (Stinkhorn fungus). Dr Paddy Sleeman
and colleagues found that Phallus fruit bodies were clumped in an area
24m to 39m (79 - 128ft) from the entrances of the four setts in their
Irish study. A linked study published in the Entomologist's Gazette more
recently recorded 12 families and 22 species of fly (Diptera) trapped at
a badger sett in County Cork during June, July and November of 1999.
Overall, the biologists suggest that badger setts attract flies -- that
is to say the death of badgers and cubs underground attracts files --
which are (blow-flies specifically) primarily responsible for the spread
of Stinkhorn fruiting bodies. The laxative effect of the fruit mucus
would then explain the clumped distribution of Stinkhorn around the
entrances to the setts. Off-hand, the data presented in these papers
seem rather circumstantial, which probably explains why the association
has been neither widely recorded or accepted.

Stinkhorn fungi aren't the only (possible) floral association and
many studies have shown that sett creation and maintenance by badgers
has a noticeable impact on the local floral community. In their study of
seven badger setts from the Rogow District of Central Poland, Artur
Obdzinski and Robert Glogowski from Warsaw Agricultural University
recorded a decline in both number and coverage of acidophilous
(acid-loving), oligotrophic (low nutrient-loving) and skiophilous
(shade-loving) plants. This decline included species from all three main
bud-height categories of flora: geophytes (buds underground),
chamaephytes (buds close to the ground) and phanerophytes (buds more
than 25cm/10in from the ground). Along with this decline, the botanists
found an increase in basiphilous (alkaline-loving), eutrophic
(nutrient-loving) and heliophilous (sun-loving) species. Included among
the promoted flora were byrophytes (e.g. mosses and liverworts),
therophytes (plants that over-winter as seeds) and hemicryptophytes
(plants that have their over-wintering buds close to the soil). It seems
that during the digging and maintenance of their setts, badgers alter
the soil properties and vegetation structure, which in turn promotes the
nutrient-, alklaline- and sun-loving species at the expense of those
which are acid-, low nutrient- and shade-loving ones. Furthermore, there
is a well-documented association between badger setts -- or more
specifically, their latrines -- and Elder bushes (Sambucus nigra) and nettles. The
latrine areas around badger setts provide favourable habitat for Elder
bushes and nettles (Urtica dioica) because as the badger dung
decomposes it releases nitrogenous components into the soil; elder and
nettles have a preference for nitrogen-rich soil. (Photo:
Sett entrances are usually easy to distinguish from fox earths --
although foxes are known to live in abandoned setts and even share setts
with badgers -- because the entrance is dome-shaped, while fox earths
tend to be more egg-shaped.)

Sett maintenance seems to be something that all clan members play a
role in, although how significant their contribution is appears to vary.
A study by Paul Steward, Laura Bonesi and David Macdonald (all at
Oxford's WildCRU) found that some 20% of clan members (adults and
yearlings) were responsible for 60 to 90% of the digging and bedding
collection that they observed during eight months of systematic
monitoring at four setts in Wytham Woods (Oxford, UK) between October
1994 and May 1996. The zoologists also observed (in contrast to similar
studies in Ireland) males to dig more than females (with boars of high
social status more likely to dig than those of low status), both sexes
to collect bedding at roughly equal rates and breeding sows to take a
more active role in den maintenance than non-breeding sows. Dr Stewart
and his colleagues suggest that by extending the sett, large
frequently-copulating boars may increase their breeding success by
creating a harem resource for several females. Similarly, they consider
that highly resident breeding females may have more to gain from
extending the sett than non-breeding sows, by reducing reproductive
competition. Indeed, unpublished observations by the same authors
suggest that some breeding females partially restricted entry to certain
parts of the sett during breeding, while previous studies by carnivore
ecologist Prof. Hans Kruuk in the late 1980s demonstrated that,
when sett expansion is restricted, there is an increase in repeated
aggression and litter infanticide between females.

In their book Badgers, Ernest Neal and Chris Cheeseman note that for
the setts studied in the UK, the relative humidity within the main sett
was always 100%, while the temperature tends to vary from 6 deg-C to 19
deg-C
(43 to 66 deg-F) even though the external temperature can vary from -4 deg-C to
33 deg-C (25 to 91 deg-F). Work by Tim Roper and Jude Moore suggests that the
primary factor influencing these maximum and minimum temperatures is the
cover surrounding the entrances; setts with woody cover surrounding the
entrances showed less pronounced variations in temperature. (Back to
Menu)

Territory: Territories of 20 to 50 hectares (ca. one-tenth of a
square-mile) are common in rich habitats, covering areas as large as 150
ha (half sq-mile) or more in poorer regions. There are typically about
10 badgers per 100 ha in 'good' British badger territory (range: 2 to
300). According to Michael Clark's book Badgers, the smaller territories
observed in badger clans from Gloucester were about 40 ha (100 acres),
with the smallest being 15 ha (38 acres). Roughly 70 ha (175 acres) was
more typical of southwest England, while in the low-density areas of
Scotland, territories were around 180 ha (400 acres). The largest
territory Clark mentions was 309 ha (773 acres) in a clan from Scotland.

Territory boundaries are marked with scent (either urine or a
hormonal secretion from glands located either side of the anus and at
the base of the tail) and dung pits (latrines -
left). Studies from Ireland
indicate that males play a greater role in maintaining the clan's
territory than the females and that these territories are fixed - i.e.
when a neighbouring badger group was removed, the clan in question did
not extend their territory to 'take up the slack' (as has been observed
in foxes). This observation is interesting considering that debate has
raged for years over what regulates the size and configuration of badger
territories. One leading theory proposes that the availability of
suitable sett sites directly determines sett density, thereby dictating
social group density; social group density in turn determines the size
of the territory. Indeed, studies from Gloucestershire suggest that when
badgers are recolonising an area, their first action is to occupy the
setts before re-establishing the territory. This implies that, at least
in some (probably lower-density) areas, setts are a crucial resource
within the clan's territory. Data from Wytham woods, however, suggest
that these badgers were constrained by food availability rather than
suitable sett sites and a change in the distribution of food (with a
subsequent increase in the carrying capacity) resulted in new setts
being dug – this is known as the “Resource Dispersion Hypothesis” (or
RDH) and seems to be the most probable explanation for badger sociality.

Badgers from the same clan will mark each other (a process known as
“musking”); a musking badger will back onto another badger with its tail
raised, secreting an odorous substance onto the conspecific’s fur. The
gland used specifically for scent marking is the subcaudal gland, which
is located in the subcaudal pouch, just in front of the base of the tail
(see: Behaviour and Social Structure).

Badgers deposit their faeces in latrines, most of which are located
either at the main sett or at territory borders (these may cover several
square metres). A study by Michael Hutchings et al. back in 2001 found
that badgers in south-west England selected woodland and avoided arable
(i.e. farmed) land, for latrine sites (which are generally shallow,
uncovered pits). They also found that faecal scent marks were
strongly associated with the edge of pastoral fields (typical of
territorial marking), rather than being in the middle.

Although territory may be defended against intruders (and studies at
Wytham Woods by Chris Newman and Christina Buesching suggest that
borders aren’t actively defended and that badgers from other groups are
able to move freely over the area provided there is no conflict of
interest with the territory holders), there is often an overlap between
neighbouring clans. This overlap seems to be related to the availability
of food. Work by Han Kruuk published in 1987 shows that the overlap
between clan territories was greatest when food availability was lowest.
This observation fits nicely with Territoriality Theory, which predicts
that a territory will only persist while conditions make it worthwhile
to maintain it; that is to say, territory systems should break down when
conditions are poor because the costs of defending a territory aren't
out-weighed by the benefits that a territory usually provides. (Back to
Menu)

Predators: Contrary to popular misconception, adult badgers do not
appear to have any natural predators across their range – although
larger predators (such as bears) may kill them to reduce competition.
Cubs are slightly more vulnerable and, in the UK, the only animals
likely to kill one are Golden Eagles (Aquila chrysaetos) and Red foxes
(Vulpes vulpes), although whether these are ever truly predatory is a
matter of opinion. In Europe Wolves (Canis lupus), Lynx (Lynx lynx),
Wolverines (Gulo gulo), Brown Bears (Ursus arctos) and Eagle Owls (Bubo
bubo - left) may take young badgers if the opportunity arises. (Back to Menu)

Food and Feeding: After the winter period, 'normal' feeding resumes
and even where large clans persist, individuals typically forage
solitarily. Tracking studies have demonstrated that clan members –
‘though not necessarily all together – will often use the same feeding
sites at different times throughout the night and that badgers tend to
move from sett-to-sett within their range, only rarely straying into a neighbouring territory. Feeding during March is typically rather
isolated, becoming gradually more social as the year progresses. Regular
social feeding is common by about April or May and large groups of
badgers feeding voraciously can be observed by September. The feeding
regime of the badger may be influenced by prevailing weather conditions
and in his book, Badgers, Michael Clark notes that gales make
feeding badgers nervous - presumably because it makes detection of
threat by scent more difficult.

Badgers are variously described as opportunistic omnivores or local
specialists, which -- throughout much of their range (and across the
entire UK) -- feed primarily on oligochaetes (earthworms). One 1981
study on badgers from six areas in Scotland concluded that the dominant
food everywhere was earthworms (Lumbricus terrestris and L. rubellus),
with some ‘less important’ food items too. This is the general pattern
across the British Isles, where earthworms constitute the primary
component of the diet – badgers seem to prefer picking these
invertebrates off of the surface, rather than digging for them. Across
their range, badgers will also take insects (including caterpillars and
moths), beetles, small mammals (including voles, rats, mice, moles,
young rabbits and hedgehogs), fish, frogs, berries, roots, bulbs, nuts,
fruit (in the autumn), fungi (esp. mushrooms) and various plant matter
(including cereals like oats and wheat). They will eat carrion and those
in urban areas are known to scavenge food from bins and gardens.

Badgers may also take birds and their eggs, although precisely how
significant they are as a predator of avians is still very much open to
debate. Anecdotal evidence (largely from the 1940s and 1950s) suggests
that badgers may occasionally be responsible for heavy losses of game
birds and it appears that in years when their preferred food is scarce,
badgers may take more birds. There is, however, little in the way of
documentary evidence to support these notions. Indeed, from the numerous
studies looking at the diet of badgers across their range, it seems that
birds represent an uncommon addition to their diet (at least at the
species level). A study by the Department for Environment, Food and
Rural Affairs (DEFRA - formally MAFF) found that out of 289 calls
regarding "nuisance badgers" in 2001 and 2002, only seven (2.4%)
concerned predation on domestic fowl. Moreover, in an extensive review
of records of birds in the diet of Meles meles by Tim Hounsome and
Richard Delahay of the Central Science Laboratory in York (UK), the
biologists report that bird remains were recorded in 2038 out of 36,699
stomach content and faecal analysis results documented in the literature
(representing 5.5% overall, or roughly 8% when considering only UK
records). They found that although the percentage frequency of
occurrence of birds in the diet increased significantly with latitude,
there was no obvious connection between the presence of birds in the
diet and season. Ultimately, while it cannot be argued that badgers will
consume birds, we cannot say with any reliability that badgers are
important predators of avians; Hounsome and Delahay, in conjunction with
several other authors, suggest that many of the bird remains found could
easily have been scavenged carrion.

In some areas, badgers may dig out and eat the contents of wasp and
bee nests, including the larvae, pupae, honey and honeycomb. Although
invertebrates such as snail and various insects can form a substantial
part of the diet, earthworms seem to comprise the primary component. A
study on a population of badgers in southwest Britain found that 75% of
individuals had worms in their stomach, with 65% having only worms.
Various authors report that it is not uncommon for a single adult badger
to eat 200 earthworms per night, especially on warm, still, damp nights,
which make for excellent worming! Indeed, throughout much of their
range, earthworms comprise about half of the badger's diet, while
mammals and insects constitute about 10% and 15%, respectively. Oxford
University’s Dr Chris Newman estimates that these 200 worms, probably
represent a maximum of 5,000 calories per night. Badgers may
occasionally break into poultry houses or take other small domestic
animals, but such instances are considered rare.

Badgers will actively predate rabbits (Oryctolagus cuniculus -
left) in
parts of their range -- which are neatly skinned, leaving only the
stomach and caecum -- and are one of two British hedgehog-eaters (the
other being the Red fox - see Q/A); foxes tend to eat the skin of the
hedgehog
(Erinaceus europaeus), while badgers leave it. Apparently, bearing
witness to hedgehog predation is not something for the faint-hearted. In
his Wildguide, acclaimed wildlife photographer and TV presenter Simon
King writes:

“Of all the predators in Britain, badgers seem best equipped to deal
with hedgehogs as a meal, digging a shallow pit next to the curled
pin-cushion, rolling it in with muzzle or fore feet, and then using
enormous power and long front claws to prize open the packed lunch. This
whole procedure is usually punctuated by very loud and pitiful screams
and grunts coming from the terrified hedgehog.”

In the UK, badgers seem particularly partial to elder berries, the
seeds of which they distribute in their dung. In a similar manner to
most other mammals, the scat can often provide vital clues to the diet
of the animal, because different foods lead to changes in consistency.
Soft scat is associated with earthworms, while more 'jelly-like'
excrement implies a predominance of berries and fruits in the diet.

As is to be expected from an opportunistic omnivore, the proportion
of various food items varies according to location and season. A study
by Eloy Revilla and Francisco Palomares published in the Canadian
Journal of Zoology in 2002 found that the main food resource for badgers
was young rabbits during the winter and spring, fruits in the autumn and
reptiles in the summer months. The scientists also report that
consumption of rabbits (both juvenile and adults) was related to rabbit
abundance, with a type-3 response (i.e. as young rabbits increased in
number, badgers slowly adjusted their diet to include more of them).
Thus, it seems that in their study area of Spain at least, badgers are
generalists and are not locally specialized. Another study by biologists
at the Euskal Herriko Unibersitatea in Spain found that the diet of a
badger clan from Biscay varied with season: fruit was a staple
constituent in summer and earthworms were the main component in other
seasons. A study of badgers in Denmark found that cereals were an
important part of the diet during the spring and autumn, with small
mammals more important during the summer months. The study also reported
that, during the autumn, males ate twice as many earthworms as did
females and that diet composition did not differ significantly with age.
This dietic variation has lead to considerable debate over trying to
describe the feeding group to which badgers belong. I think that
Carnivore biologist Prof. Han Kruuk, formerly of Aberdeen University in
Scotland, sums the situation up quite nicely in his book Hunter and
Hunted, in which he writes:

"More complicated still, the Eurasian badger, for instance, may be
highly focused in its food selection in any one area, concentrating on
earthworms in northwest Europe, on rabbits in southern Spain and on
olives in northern Italy. There is no doubt that in each of these areas
badgers are highly specialized compared with the other predators around.
Nevertheless, their specializations are different in different places.
There is still earnest scientific debate about whether this animal is an
omnivore or a specialist (I call it a local specialist)."

If one were wishing a more cautious approach to classifying a
badger’s feeding habits, try the definition given by Universidad Rey
Juan Carlos' Emilio Virgós and his colleagues in their 2004 contribution
to the Canadian Journal of Zoology, where they describe Meles meles as:
"facultative specialists that search preferentially for earthworms but
probably take other food resources during their foraging bouts (beetles,
fruits, and fungi)."

Regardless of the trophic 'category' to which you choose to assign
Meles meles, in most populations, badgers feed copiously in the spring
and summer months and have laid down appreciable subcutaneous (under the
skin) fat reserves by the autumn. Indeed, from September to November
badger switch to an anabolic metabolism (to lay down fat), switching
back to a catabolic metabolism in December to allow fat store to be
utilised. This layer of fat can be considerable and may increase the
badger’s weight by as much as 60%. Indeed, many consider the abundance
of food resources to be ultimately responsible for the great variation
in badger sociality (i.e. it is the underlying cause of badgers living
either solitarily or as groups); recent work from Poland and Oxford
certainly seems to support this idea.

Contrary to popular perception, Red foxes don't appear to compete
directly with badgers for food; in fact, the two (esp. fox and badger
cubs) can often be seen foraging together on good feeding grounds. An
interesting paper -- published recently in the Journal of Zoology
-- by
David Macdonald, Christina Buesching and colleagues found that foxes may
sometimes seek the company of badgers (presumably as a method of finding
some of the best foraging grounds). Even when foxes are tolerated at
feeding sites, badgers still have dominance, readily seeing off any
foxes that overstep their mark. Unlike the Red fox (and many other
carnivores), badgers are not known to cache surplus food.

Badgers rarely drink; instead they obtain most of their water from
their food. Despite this, putting out water can be invaluable for
cubs visiting your garden. One of the biggest causes of cub death is coccidiosis; coccidiosis is intestinal inflammation caused by
single-celled protozoa (in badgers, Eimeria melis and Isospora melis).
These coccidia develop in the cells of the intestinal lining and, as
they reproduce, they cause serious intestinal bleeding, which leads to
very watery diarrhoea. Consequently, the cub loses substantial amounts
of water as well as salts and various nutrients (dissolved in the
water). Although adults develop an immunity to this parasite (if they
get the chance!), cubs have not yet received sufficient exposure for an
immune response to develop. Ergo, if you have cubs visiting your garden,
put out a saucer of water for them - ultimately, water is far more
important to a cub with coccidiosis than food. (Back to Menu)

Breeding Biology: Badgers become sexually mature at one year old and
mating may occur during any month, although the majority are between
February and May (mating is also quite common between July and
September). Oestrous (the female’s receptive period) in Meles is
typically between one and two days, during which a sow may mate with
several boars (prior to this, a boar's testicles descend following the
over-winter retraction that acts to conserve heat). During courtship,
the male will pursue the female and bite her nape (back of the neck)
during intercourse. Reports exist describing the sow running around in
circles -- first clockwise, then anti-clockwise, similar to that
observed in courting hedgehogs -- prior to copulation, although it is
unknown whether this is common behaviour. In a talk about the badger’s
natural history to a team of Earthwatch volunteers (of which I was
fortunate enough to be one) in May 2006, Christina Buesching spoke of
the behaviour of boars at Wytham during the breeding season. Dr. Buesching described how each night one boar would wander around the
sett, sticking his head into each of the entrances and making a
“churring” noise (which sounds similar to gargling with a very full
mouth). If a receptive sow doesn’t answer (or come out), he moves on to
the next hole and repeats the churr. The following night a different
(but again, only one) badger will patrol the sett.

In their 1996 edition of Badgers, Ernest Neal and Chris Cheeseman
describe some mating events. The biologists write:

"The first sign of interest shown by the boar is often the raising of
the tail into a vertical position and the emission of a loud and often
continuous deep whinnying purr. He may then approach with a shuffling
motion taking short steps with the legs kept rather rigid."

Other descriptions note the presence of mutual grooming and 'ground
pawing' by the boar immediately prior to mating. Many field reports
describe vocal 'utterings' between badgers during copulations, serious
attempts at which may last anywhere from ten minutes to one-and-a-half
hours; intercourse of two to five minutes is known in sows that are not
fully receptive. Mate-guarding (i.e. males chasing away competitors from
their chosen mate) is known in badgers and, in some respects, badger
clans are similar to the pride system observed in lions; sows are able
to move into neighbouring territories where they are apparently free to
mix with other badgers and leave when they please, frequently after
mating. Once mating has taken place, females bear all the costs of
reproduction and males play no role in raising the cubs.

In a study of 548 adult female badgers from Offaly in Ireland between
1989 and 1990, Thomas Hayden and Robert Whelan found that between 80%
and 90% of females mate, only 65-70% achieve successful implantation and
of these only 35-40% exhibit copious lactation. These figures are
similar to results from studies on badger populations in southern
England, where about 30% of females breed annually. The Irish paper goes
on to report that reproductive performance of yearlings was inferior to
older badgers and observed some evidence for density-dependant
reproduction in this species (i.e. reproductive success was correlated
with the number of badgers in the population).

After fertilization, sows undergo a phenomenon known as embryonic
diapause (also referred to as ‘Delayed Implantation’). Diapause is a
dramatic reduction in, or a cessation of, mitosis (cell division) in the
zygote (fertilized egg) at the blastocyst stage. In other words, the egg
multiplies to form a hollow ball of cells (called a blastula), which is
then suspended in the uterus for between three and 15 months, although
the latter is rare. Currently, reproductive biologists divide those
species displaying embryonic diapause into those which are facultative
(i.e. delayed implantation is induced by environmental conditions, such
as in the rodents and marsupials) and those that are obligate (i.e. that
present at every gestation regardless of ambient conditions). Badgers
are placed within the obligate class and, almost regardless of the time
that mating actually takes place, a sow will delay implantation until
late December or early January. So this, as well as the wide
distribution of embryonic diapause among unrelated taxa (e.g. plants,
insects, vertebrates) -- which suggests that it has arisen several times
during the course of evolution -- raises the question "what is the point
of delaying the implantation of the blastula?" It has been suggested
that diapause might allow mating to move to the most optimal times (such
as when females are best able to select high quality mates) or that it
may relate to the storage of sperm.

In 1880, S. Fries proposed that delayed implantation may allow the
young badger cubs to be born earlier in the growing season, thus
providing them with the maximum length of time possible to develop
before they had to face their first winter. Some 126 years on, Fries'
hypothesis is still considered the most plausible explanation for this
phenomenon. Indeed, in their recent paper to the journal Evolution,
Michael Thom, Dominic Johnson and David Macdonald of Oxford University
argue that delayed implantation is a plesiomorphic (i.e. primitive)
characteristic in mustelids, which evolved several times (probably
because there are costs associated with it). The observation that
delayed implantation increases in frequency as you move further from the
equator, argue Thom et al., strongly supports the idea that it provides
the beneficial trait of being able to uncouple mating and parturition.
In other words, diapause permits sows the luxury of being able to select
mates at premium times (e.g. when males have survived a particularly
harsh season) while allowing births to coincide with the most favourable
seasons.

While there has been much speculation as to the purpose of diapause,
the biochemical cause of this phenomenon has yet to be established. It
has been suggested that hormones in the badger’s blood (e.g.
progesterone and oestrogen) and possibly some proteinacious development
factors are responsible for triggering resumption of blastocyst
development. Indeed, studies in rodents have suggested that the female
sex hormone estradiol and Epidermal Growth Factor Receptor (Egfr) may
play a role in triggering blastocyst implantation; a single injection of
the female sex hormone oestrogen has been shown to terminate diapause.
Similarly, work on badgers by Rene Canivenc at the Universite de
Bordeaux II in France has demonstrated a pronounced increase in luteal
vascularization and progesterone production prior to implantation.

In April 1979 a paper published in Nature reported on the experiments
of Rene Canivenc and colleague M. Bonnin on captive sows. The biologists
exposed six sows to a 10:14 photoperiod (i.e. 10 hours of light,
followed by 14 hours of darkness) at 5 deg-C (41 deg-F). Blood samples were
taken from the badgers each week and analysed for progesterone.
Progesterone is a steroid hormone that is secreted by a small, temporary
endocrine structure in the ovary called the corpus luteum - in mammals
it is known to prepare and maintain the uterus for pregnancy. The
scientists found that when the photoperiod was decreased (i.e. more
dark, less light), there was a sharp increase in progesterone levels to
those seen just prior to implantation during January in wild specimens
(18 and 20 nanograms per mL, respectively). Through
manipulation of the photoperiod, Canivec and Bonnin were able to induce
"whelping" (i.e. birth) during September, when in the wild the litter
would not have been born until the following spring. Ultimately, Canivenc and Bonnin
succeeded in demonstrating that delayed implantation in the Eurasian
badger (under artificial conditions, at least) is apparently controlled
by environmental factors (namely temperature and light, with earlier
implantation induced by increased night length), rather than -- for
example -- some genetic predisposition to implant after a given period
of time. Subsequent experiments by the same authors, during which the
temperature was controlled, suggested it to be light levels that
triggered implantation.

While these experiments are certainly appealing and doubtless give us
a good idea of some of the factors at play here, they do not seem to
tell the whole story. As Neal and Cheeseman point out, there are several
flies in this ointmental logic! Among the problems is the fact that from
about October-time onwards, badger emergence is entirely nocturnal and
not obviously correlated with sunlight; also that implantation should be
earlier at northern latitudes (because night length increases more
dramatically and temperature drop is more pronounced) when the reality
is quite the opposite. Furthermore, there are -- admittedly rather rare
-- records of two sows living in the same sett giving birth several
weeks apart.

Data from Stephen Ferguson and colleagues at the University of
Saskatchewan in Canada suggest that reduced nutrition in the sow can
lead to a lengthening of the diapause period. More recent work seems to
support this idea and an interesting experiment by a team at the
University of Oxford found that when females had a relatively high index
of body condition (i.e. were healthy and well fed), they implanted early
and the cub sex ratio was male biased (i.e. more males were born than
females). The important point here is that their finding goes against
the reasonably well-established Local Resource Competition Hypothesis
(LRCH). The LRCH states that in years when female body condition is poor
animals should lower competition for local resources by producing males
(i.e. males are more likely to disperse, rather than hang around and use
some of the scarce local resources).

Studies on the badgers of Wytham Woods in Oxford have suggested that
body condition in sows is probably very important in determining
implantation. The WildCRU biologists have found that females in poor
body condition during the winter frequently reabsorb their blastocyst –
females can even reabsorb embryos if they decide that they cannot carry
it to term. In Wytham, about 95% of sows at reproductive age have
blastocysts in their uterus and, by January, about two-thirds of these
have embryos. About half of the aforementioned two-thirds give birth and
about one-fifth of females lactate in any given year. Typically, only
two sows per sett seem able to raise cubs to the point at which they
appear above ground (representing about 5% of the population).

The connection between fat and hormones does seem to be an important
one and Ernest Neal speculates that, given the lipophilic tendencies of
steroids (i.e. they are fat soluble), hormones may be incorporated into
the fat reserves built up during the summer and autumn. When the sow
enters winter torpor, she begins to live off her fat reserves and as the
fat is metabolised, the hormones are gradually released into the
bloodstream (it may be this process that triggers implantation). There
are various lines of indirect evidence that seem to suggest that this is
a plausible theory and, if correct, this would make the quiet, rather
inactive month of December a crucial time for the triggering of
blastocyst implantation. Indeed, field observations seem to indicate
that disturbed setts produce fewer litters than undisturbed ones.

When the aforementioned observations are combined with reports from
the field, which suggest that litters are closely tied with food
availability (i.e. in years of poor food supply cubs are often later
than usual), it becomes clear that the trigger for implantation still
begs research. Ultimately, it is probably a combination of light,
temperature, current body condition and food supply that interact to
trigger implantation.

Once implantation of the blastocyst has occurred, gestation is
usually between six and eight weeks, with cubs born anywhere from
mid-January to mid-March with the bulk occurring in early February.
Births have, however, been recorded anytime from mid-December to April and,
because badgers slow their metabolism in winter, gestation can last for
between 37 and 20 days (average 63 days). A female may produce as many
as six cubs, although two is most common and studies from Ireland have
recorded in utero litter sizes of between one and four young. Typically,
any given female will only produce one litter in a single year, although
under plentiful conditions more than one female in the clan may
reproduce. In common with all mammals, the young are altricial
(i.e. born blind and helpless). Neonatal (newborn) badgers are thin with
pale grey fur and measure about 12 cm (5.5 in.). The cub’s eyes open
after about five weeks.

The majority of cubs are born underground in a specially modified
chamber close to the sett entrance, with good ventilation and a mass of
bedding that is moved in prior to the birthing; on the basis of captive
badger births, it has been suggested that the temperature inside the
natal chamber is 18 to 20 def-C (64 - 68 deg-F). In rare instances
however -- for example where the expectant mother is a subordinate sow
looking for somewhere to give birth away from the attention of the alpha
sow, but rising of the water table and soil type combine to prevent den
excavation -- a sow may give birth above ground in large mounds or
straw, hay, grass and/or reeds.

Young badgers
(right) emerge from the nursery chamber at about eight weeks
old (late April or early May) and the cubs have their first teeth at
four weeks old. The permanent dentition is complete by 16 weeks (ca. 4
months). Weaning begins when the cubs are about 12 weeks old and during
this process the sow will regurgitate food for the cubs; cubs are weaned
and feeding themselves by five to six months old (around end of June,
early July). Cubs may be seen foraging with the sow by summer and by
June all the juveniles will be familiar with the clan's territory.
Badgers are unique among social mammals in that the cubs do not appear
to be the central focus of the group, instead they are largely ignored
by the adults and it is always the cubs who initiate play with adults,
never vice versa (see Q/A).

By the time the cubs are fully weaned, if conditions are good the
juvenile badger may weigh 6 kg (13 lbs). If the cub survives to the end
of its first year, it will usually weigh between eight and ten kilograms
(19 – 22 lbs) and measure 70 to 80cm (2.5 ft). One study from Ireland
published in 1993 observed that more than 60% of cubs died during their
first year, 35% to 40% of which died before they were weaned. Similarly,
although when taken overall, the number of both sexes dying each year is
approximately equal; substantially more males are known to die earlier
in the year, with females dying later in the year. Presumably this trend
reflects the tendency for males to be bolder and thus explore further
from the relative safety of the sett than females.

On average both males and females mature at 12 to 15 months old,
although males may mature as late as two years and females may begin
ovulating earlier or later than the average. Dispersal is most common in
badgers of two years old and seems intrinsically related to clan
stability (i.e. the more stable the habitat and social dynamics of the
clan, the less likely dispersal becomes). Males generally have a greater
tendency to disperse than females. In a paper to the Joural of Mammalogy
during 2008, David Macdonald and his team analysed 17 years of
data from a marked population of badgers in Oxford and report that 36%
of individuals never dispersed from their natal territory and, of those
that did, dispersal distances rarely exceeded two or three home
range diameters. These data support previous studies, which have found
that while excursions into neighbouring territories for the purposes of
(inter)breeding may be common, as a species, badgers have low dispersal
rates and at a local (although not at the species) scale are genetically
depauperate (i.e. local mixing of genes is severely diminished) – the
global population appears to have gone through a genetic bottleneck at
the last Ice Age.. Where dispersal does occur, sows may leave the clan
in 'coalitions' of two or three animals.

Generally, about half the cubs will die within their first year
through causes other than infanticide (i.e. the weather, disease, on the
roads etc.) and there is often a 30% per annum mortality of adults.
While disease and road accidents are invariably important features in
the overall mortality of badgers, weather seems to be perhaps the most
significant factor. In a paper to the Journal of Zoology in 2002, a team
from Oxford University's WildCRU lab report on the population dynamics
of the badgers living in Wytham Woods (Oxfordshire, UK) between 1987 and
1996. During this time, the population experienced a terrific increase
in both badger numbers -- almost quadrupling from 65 adults to 228 --
and badger density (15 adults per sq-km in 1987 to 38 adults per sq-km in
1996). Despite the overall trend in population increase, however, cub
survival was inextricably linked to rainfall. In 1990, a summer of
unusually low rainfall resulted in 15 of the year's 23 cubs (65%) dying,
although rainfall seemingly has little impact on the number of adults
surviving. Presumably, during prolonged periods of dry weather,
earthworms are scarce and difficult to dig for, leading to a decline in
overall body condition and an increased chance of cub mortality.
Fortunately for the badgers of Wytham, their population appears to have
grown in response to an overall improvement in climatic conditions as
well as the social rearrangement of territories observed during the
study. (Back to Menu)

Behaviour and Social Structure: European badgers are atypical among
the mustelids because in parts of their range they live in highly social
family groups (clans) and yet show little sign of any cooperative
behaviour. Clan formation is typically associated with areas abundant in
resources and with high population densities; in areas where badger
density is low (e.g. Scottish highlands and Scandinavia), clans tend to
consist of a "basic unit" (one male and one female) and very
occasionally a couple of related individuals.

Where subordinates persist, they do not appear to be “helpers” in the
same way that can sometimes be seen in Red fox (and other canid)
communities. Studies on the alloparental behaviour (i.e. individuals
raising cubs that aren't their own) of badgers have provided mixed
results. The vast majority of observations have failed to find any
evidence that subordinates help breeding individuals. Indeed, a recent
scientific study, published in the Journal of Zoology, found that
breeding sows with 'helpers' were actually in worse condition at the
close of the breeding season than those without helpers! The study found
that the majority of non-breeding females (helpers) were sexually mature
adults that had lost their own cubs and concludes that the negative
effect of helpers was probably a result of intense competition for
resources. Despite these results, however, some reports of alloparental
behaviour do exist. In a paper to the journal Animal Behaviour back in
1993, Oxford University zoologist Rosie Woodroffe writes of non-breeding
sows babysitting and grooming cubs. Dr Woodroffe describes babysitters
rounding up cubs that strayed too far from the sett, chasing a fox and a
boar (who bit one cub) from the sett and mutual scenting (i.e. cubs
marking babysitter and babysitter marking cubs). On three occasions,
Woodroffe observed a mother and a subordinate carrying the cubs from the
burrow where they slept with their mother to the burrow where the
babysitter slept. In her paper, Dr Woodroffe suggests that such
examples of alloparental care may have been missed during previous
observation because the watchers mistook babysitters for mothers. She
also suggests that babysitting may occur earlier in the year, before the
cubs emerge from the sett.

Coupled with Woodroffe's observations, there are reports of apparent
kin selection (i.e. relatives caring for offspring that aren’t theirs)
from badgers, although such instances seem very rare. Overall,
subordinate badgers don’t seem to have any input in raising the year’s
brood; even taking Woodroffe's work into account there are no reports of
subordinates suckling the cubs, or providing food for the mother or
cubs. Moreover, observations from Wytham Woods have found that
adults to not even take cubs underground when danger threatens. Instead,
subordinates seem to perform general sett maintenance duties, such as
expansion of the sett and changing of the bedding. Presumably, this
assistance is particularly helpful during late winter and early spring
when bedding may be dragged out of the sett and left in the entrance to
'air', which one assumes kills off lice, ticks and fleas that can
parasitize badgers. The airing of bedding may be a crucial factor in the
maintenance of the sett and there is some suggestion that at least some
instances where badgers have 'upped-sticks' and moved setts may be the
result of parasites building up in the bedding.

Several studies have demonstrated that, across Britain, the average
number of breeding females per clan decreases with increasing latitude
(so Scottish clans typically contain only a single breeding sow, while
several sows may reproduce in clans from southern England). Indeed, in
high-density populations (such as those observed in south-west Britain),
group sizes may be considerable (the record currently stands at 23
individuals, three of which were lactating sows). In these groups, where
several reproducing females may co-exist, it appears that although sows
compete directly for breeding status (the number breeding being directly
related to the quality of the clan's territory), there is little
competition between them thereafter. Furthermore, data from these groups
suggest that, in high-density populations, reproductive suppression is
mediated through female-female competition for resources, rather than
through a need for co-operative care of the young (as has been
demonstrated for other social carnivores). In other words, reproductive
suppression is a mechanism for adjusting the group size to fit the
availability of local resources instead of being a way of coercing clan
members into babysitting. This idea is given further weight by studies
from Sweden, Spain and Italy, which have found that when food is very
scarce, badgers abandon the concept of sociality altogether and live
alone or in pairs. Even where groups persist, there may be 'tiers' of
affiliations. Work in Oxford has demonstrated that not only do sows
sometimes show a preference for sharing sleeping chambers with other
females, but sub-adult boars have been observed to form 'loose
associations', spending more time with each other than other clan
members.

Badgers within a given clan are usually closely related (although
more than one family may sometimes make up a single sett) and establish
a well-defined territory marked by scent and latrines (see Territory
above), which they will vehemently defend against intruders if need be.
Despite the territoriality associated with the sett and latrines,
feeding grounds may overlap with neighbours and to date there are no
confirmed records of a hierarchy among badgers (either between members
of the same clan or between members of peripheral clans) feeding at the
same location, although there is evidence that during times of limited
food resources, adults may restrict access to key foraging areas by
subordinate clan members. Indeed, based on computer models, some
consider that badgers make use of a passive range exclusion mechanism.
This concept suggests that feeding excursions deep into neighbouring
territories aren't worth a badger's time and energy, because areas of
lower food availability are encountered and the travel time (returning
to their own sett) is lengthened. The idea is that badger territories
are roughly hexagonally-shaped areas, each border touching that of a
neighbour's range, such that they form a honeycomb mosaic. Each sett is
roughly in the middle of the territory and badgers forage closest to the
sett first, moving further away as they exhaust the food reserves. The
upshot of this is that 'ridges' of higher food availability build up at
the periphery of each range (because these sites are visited less often
than those closer to the sett). If we remember that every badger clan in
this mosaic is doing the same thing (i.e. eat outwards from the main
sett), we can see that although it is worth the effort to walk up to the
edge of your territory, the further into your neighbour's territory you
go, the less food you're going to encounter. This means that, when you
weigh-up the pros (i.e. food) with the cons (i.e. further to walk, more
danger of attack from resident etc.), it is simply energetically
unviable for a badger to wander outside its own clan's area when looking
for food. Thus, these territories can be maintained passively, through
exploitation competition and feeding optimization. The benefit of this
is that the badgers don't need to put themselves at risk by seeing off
intruders who are trying to raid their larder. This is not to say that
aggression is either unnecessary or uncommon -- several studies suggest
quite the opposite -- but it does suggest that aggression may be
unnecessary for some aspects of badger territory perpetuation.

Interestingly, countless hours of direct observation have failed to
demonstrate any dominancy hierarchy among badgers – many badger
biologists consider that there is a hierarchy, and observations by
amateur enthusiasts seem to support this idea, but that it is probably
our finite methods of observation fail to detect it. The question is
really, if this hierarchy does exist, what benefits do dominant animals
reap? After all, they certainly don’t seem to provide more food, or more
mates. Despite a lack of evidence to suggest a stable social hierarchy
in badger groups, fighting between clan members is well known and
typically escalates from jaw-to-jaw contests to neck and frequently rump
biting. Where direct aggression does occur, the resulting wounds can be
serious. Work by Glen Cousquer, Veterinary Officer at the RSPCA Wildlife
Hospital in Taunton (UK), shows that fight injuries can vary from
incidental puncture wounds to large suppurative (i.e. pus-discharging)
wounds. In an article to the World Wide Wounds website, Cousquer writes:

"Bite wounds often penetrate deep into the dermis, introducing
bacteria into the subcutaneous tissues and setting up foci of infection.
In some badgers these foci of infection burst out and coalesce,
resulting in large open wounds that may subsequently become flyblown
[maggot-infested]. Many badgers cope well with their wounds and it is
not uncommon for badgers to be seen at the hospital with incidental
wounds, requiring little or no treatment."

Cousquer goes on to say that upon successful healing of a bite wound
(see right), the badger is often left with an area of tough scar tissue,
which may provide some protection from further aggressive interactions.
A more recent paper to the journal Animal Behaviour by the mammal team
at Oxford University's WildCRU reports that not only did males (and
especially heavier males) receive more bite wounds than females, but
that wounding rates (again particularly in boars) showed a
density-dependent increase (i.e. as the population increased, so did the
frequency with which males were observed to sport bite wounds). The rate
of bite wounding in males was also seen to increase as the number of
badgers living in adjoining territories increased. This, coupled with
the observations that males were injured at about twice the frequency of
females and that older individuals were more likely to sport bite
wounds, suggests that the defence of territory may be a significant
cause of these injuries. The biologists note that severe wounds were
fairly infrequent in individuals less than three years old, which
implies that -- assuming this rate wasn't masked by individuals moving
away and dying -- agonistic encounters are typically restricted to
badgers of breeding age and thus these fights are a result of social
tensions. Interestingly, Prof. Macdonald and his colleagues failed to
find any correlation between bite wound frequency and season, which is
in contrast to both Dr Cousquer (who observed more bite-wounded
casualties during February and March) and Dr David Dixon (who documented
higher levels of intraspecific aggression on nights when the moon was in
its new phase - see: Activity).

An example of a fight wound, usually obtained
during territorial disputes. The image on the left shows the wound
shortly after infliction with what appears to be serious tissue trauma
to the rump. The image on the right shows the same badger approximately
one month later - no veterinary treatment was provided.

There is still debate as to the underlying cause of group formation
in badgers. Classically, an ecological principle called the
Resource
Dispersal Hypothesis (or RDH, for short) has been used to explain clan
sociality. Recent work conducted in Spain suggests, however, that this
may not be accurate. The RDH states that the size and configuration of
areas defended by an animal (or group of animals) is decided on the
basis of food availability. In the social primates, for example, work
during the late 1970s demonstrated that those which feed primarily on
foliage often have smaller territories than those which feed principally
on fruit; this is believed to reflect the more sparse distribution of
fruit compared to foliage (i.e. fruit is less abundant than foliage and
so the primates have to move over a wider area in order find sufficient
to satisfy their hunger). In the case of badgers, the spatial aspect of
the RDH (referred to as RDHS) is frequently applied. In essence, where
an important food resource is sporadically distributed, a pair of
animals will decide upon the minimum area that can be shared with their
conspecifics before competition for the food becomes likely. Within the
context of this theory, badgers are referred to as "contractors",
because they should maintain the smallest economically defensible
territory with sufficient resources to permit reproduction (i.e. the
smallest patch needed to support them throughout the year, without
expanding). Recent data from the Donana region of south-western
Spain, however, suggests that the RDH doesn't account for the group living in this
population of badgers. The study found that for this population, female
territoriality was driven by food availability, while male
territoriality was driven by female availability. Additionally, the
ranging behaviour of males suggested that they were 'expansionists',
rather than 'contractors' and overall territory size was related to its
richness, rather than the patchiness of its resources. While these data
certainly don't disprove the RDH for badgers as a whole, the biologists
suggest that there is a better hypothesis to explain the sociality of
badgers in this sub-humid (i.e. long summers) area of the Mediterranean.
Rather than a single factor -- i.e. food distribution -- governing the
formation of groups, they suggest that a myriad of factors (the
availability of key resources, the impact of the dispersing individuals'
mortality on the population demography and other behavioural constraints
that may favour philopatry over dispersal) may integrate to influence
whether an animal stays on its parents' territory or moves away to find
its own place.

Whatever the underlying cause(s) of group formation in badgers, scent
plays a pivotal role in group and territory maintenance, with clan
members generally carrying the scent of the dominant boar. Valuable
tools in the act of scent-marking are the subcaudal gland (which is
close to the anus and imparts scent on to the faeces) and the paired
scent glands located just inside the anus - anecdotal observations
suggest that scent glands between the toes (i.e. interdigital glands)
may also be used when marking objects such as trees near the sett.
Arguably the most important scent-marking tool is the subcaudal gland
(SCG), which is used to mark objects in the territory as well as other
members of the clan (a process referred to as 'allomarking' -
below). The SCG
develops from sweat glands and consists of a pouch (the Subcaudal Pouch,
or SCP) lined with several layers of sebaceous (cells that secrete an
oily lubricant onto the skin and hair) and holocrine cells (those that
release their secretion by disintegrating the cell itself), while the
pouch itself is partially divided into two sections by a membrane
(giving a heart-shaped appearance). The SCP opens to a horizontal slit
(between 2cm and 8cm -- just under 1in. to just over 3in. -- wide)
situated between the base of the tail and the anus.

Allomarking badgers - the cub on the left is
applying subcaudal gland secretion to the back of the adult badger on
the right. This mixing of scents helps to maintain a 'group odour' and
aids recognition within the clan.

The gland secretion has be likened to a margarine-like paste,
predominantly composed of long-chain (unsaturated) fatty acids with a
little protein and water – the odour is generated by the bacteria in the
pouch. Data from Wytham’s badger population show that every individual
has a different mixture of compounds in their SCG secretion because the
species of bacteria in the pouch determine the type and rate of compound
metabolism. This means that each badger gas its own individual scent.

A series of recent experiments carried out by a team of scientists,
fronted by Christina Buesching at the University of Oxford, has provided
some interesting information on the composition and variability of SCG
scent. In one set of tests, Dr Buesching and her colleagues used gas
chromatography to determine the composition of the SCG secretion. Gas
Chromatography is a process during which a sample of a given substance
is vaporized and injected into chromatographic columns; in these columns
it separates into its individual components allowing the individual
ingredients to be identified and measured by a piece of equipment called
a mass spectrometer. Effectively, a gas chromatograph can be thought of
as a “mechanical nose”. The biochemists were able to identify 110
different components, 21 of which were present in every sample (this has
since increased to about 32 out of roughly 150). Of particular interest
was the discovery that the SCG secretion shows distinct seasonal and
clan-specific variation. Buesching's experiments found that clan
member secretion-chemistry was more similar to members of their own
group than to those from outside the clan; the composition varied
according to season, sex, age, body condition and reproductive
status. These results suggest that not only does the SCG’s secretion
convey information about clan membership, but it may also provide
information about the health and fitness of the individual.

A second paper by Dr. Buesching and colleagues found that not only
did sex have important implications for SCG properties (males had larger
glands, containing more secretion than females), but so did reproductive
condition and season. Although the paper reports that there was no
observable effect of pregnancy and lactation on secretion colour or
volume, there was a significant negative correlation between the levels
of progesterone in the blood and the volume of SCG secretion during the
spring and summer (i.e. the more progesterone, the less SCG secretion).
For males, those in breeding condition (i.e. with descended testes) had
substantially more secretion in their SCG than non-breeding males,
although this finding couldn't be linked to the levels of testosterone
in the blood. Reproducing boars also had a significantly whiter
secretion than their non-breeding counterparts, although overall sows
had consistently darker SCG secretions than males, with the secretions
for both sexes found to be darkest during spring.

Allomarking (above) is frequently observed in badgers and -- according to a
paper by Han Kruuk, Martyn Gorman and Alan Leitch published in the
journal Animal Behaviour in 1984 -- can be split into two categories:
mutual or sequential. "Mutual" allomarking involves two badgers pressing
their SCPs together simultaneously, while "Sequential" (or "One-Way")
allomarking is characterised by one badger marking the body of another.
In a 2003 paper to the journal Behaviour, WildCRU scientists Christina
Buesching and David Macdonald and biologist Pavel Stopka from the
University of Charles in Prague report their observations of allomarking
in the badgers of Wytham Woods between November 1994 and April 1996. The
zoologists found that sequential allomarking was significantly more
common than mutual marking, occurring in 2,866 of 3,021 instances (~
95%); mutual allomarking was only observed 155 times (~ 5%). Both forms
of allomarking were considerably more common during the mating and
cub-rearing seasons (winter and spring, respectively) than at other
times in the year and although females showed no preference for the
marking of one sex, boars -- which also marked more prolifically than
females -- preferred to mark sows, although neither sex marked a
specific individual preferentially. Males also seem to mark sows
post-mating, a feature that Dr Buesching likens to giving her a wedding
ring (in other words, saying: “I’ve mated with her, she’s mine!”).
Further, yearlings and juveniles were seen to mark most frequently
(musking adults of the same sex) and non-breeding sows musked breeding
sows more commonly than vice versa. (Diagram:
Approximate location of the anus and subcaudal gland (SCG) of the
badger. Modified from Neal and Cheeseman, 1996.).

The observation that males marked more than females corresponds
nicely to previous work by the same zoologists (see above), which found
that males hold substantially more secretion in their SCPs than females
and that both sexes produce more secretion between January and May
(corresponding to the peak allomarking period). Another interesting
finding of this study was that, while mutual marking varied according to
sex and season, sequential marking was dependant upon factors such as
age and reproductive status (i.e. fitness-related parameters); this
implies that the two forms of marking may have, at least partially,
different functions. Given that the process involves the exchange of
minute quantities of SCG and facilitating the mixing of SCG flora, Dr
Buesching and her colleagues suggest that allomarking may serve to
maintain a common 'clan scent' – this explains why allomarking only ever
occurs between members of the same clan. Sequential marking, on the
other hand, is probably more involved in advertising individual-specific
information (using your clan members as billboards that advertise your
status), with perhaps the added function of distributing the clan scent.
Indeed, some fascinating data from the WildCRU team was that the
secretions degrade in a specific way, with two components breaking down
rapidly (over a period of hours) while others barely change. The
scientists hypothesise that these two rapidly-degrading components
represent the oestrous marks, meaning that a passing boar coming into
contact with the scent several days later won’t waste time and energy
tracking down the sow (who will have since finished oestrous), but will
still be able to read the other messages encoded in the scent (i.e. her
age, sex, clan etc.) – the remainder of the scent will persist for about
two weeks.

Overall, these specific group odours are thought important for intra-
and interclan (i.e. within and between groups) communication. Indeed,
badgers are well known to be able to distinguish between the subcaudal
secretions of clan members, neighbours and unfamiliars, while studies on
peccaries (wild pigs of the Tayassuidae family) and mice have shown that
group odour can reduce aggression between conspecifics.

The frequency with which a badger deposits its scent on the territory
varies according to a host of factors, including reproductive status,
season, sex and location on the territory. A paper to the journal
Acta
Theriologica in 2004 by Christina Buesching and David Macdonald reports
on how scent-marking by badgers in Wytham Woods changes according to
these factors. The act of SCG scent-marking takes about a second and
involves the badger squatting (with a bending of the knees and a raising
of the tail) and pressing the semi-circular shaped opening of the SCG
against the substrate (frequently a prominent object such as a tuft of
grass or rock). Between April 1996 and June 1997, 442 incidences of
object-marking were observed, the frequency of which varied with the
season as well as the sex, age and reproductive status of the badger;
reproducing badgers scent-marked more frequently than non-reproducing
ones, adults scent-marked more frequently than juveniles and, during the
cub-rearing season, females scent-marked more frequently than males.
Females were seen to over-mark (i.e. re-apply the scent to the exact
same area) more frequently and more consistently than males, who only
over-marked during the mating season; overall, roughly one-third of
scent-marks were over-marked within 24 hours. Buesching and
Macdonald conclude that, based on these data, not only do scent-marks
play a role in signposting territory boundaries, they also serve as
advertisement signals directed at other group members.

Complementary to the scent laid down by the SCG are scents from
urination and faeces. In their 2004 paper, Buesching and Macdonald
observed badgers urinating on top of their sett, either in specially dug
pits, on the grooming area or (most frequently) on the spoil heap.
Urination typically involves squatting, although boars have been
observed to perform raised-leg urination. Various studies have
demonstrated that urine scent-marks may be used to over-mark the scent
left by foxes, while scenting in general is carried out along the main
foraging path before the badgers begin to forage more widely. The
badgers then find their way back to this path, which shows them the
route back to their sett. It has been suggested that countless
generations marking the same feeding route may explain why, even when a
field is ploughed, the badgers can re-establish the exact same path and
also how badgers collecting bedding unerringly find their way back to
their sett without looking where they are going (bedding is brought back
to and carried down into the sett backwards). It may also help explain
the results of a fascinating study conducted by a team of biologists in
the Croix-aux-Bois forest of northeastern France in 2003. This
particular study found that if you take a badger away from its home sett
and release it somewhere else on its territory it homes (i.e. finds its
way back to the main sett) quickly, while if you release it in the home
range of one of its neighbours', it will also find its way back after
wandering randomly for a while (presumably getting its bearings).
If you release this badger outside the home range of its neighbours (regardless of the distance),
however, it fails to find its way back
home. These results are interesting because they suggest that badgers
may recognise neighbouring (that is to say contiguous) territories as
being close to their own.

Faeces are often considered to be a more robust marker than urine.
Although the faeces itself may not smell particularly pungent to us, the
anal sacs empty into the rectum and coat them with a jelly-like
substance that probably smells stronger to other badgers. Badgers
generally deposit faeces into specially dug -- not to mention
strategically placed – latrines, which are located close to the sett,
along well-used foraging paths and at the territory boarders. Young
badgers often use latrines throughout the territory (so-called
‘hinterland’ latrines), using communal ones as they get older. Indeed,
observations on captive badgers suggest that scenting behaviour starts
when they’re about nine-weeks old (with females showing a greater
tendency to scent-mark than males), although more recent biochemical
observations suggest that cubs don't begin producing SCG secretion until
they are about four months old. As Ernest Neal and Chris Cheeseman point
out in their book Badgers, the captive observations correspond
to roughly the age at which wild cubs begin to leave the sett. They also
comment on how living in an area permeated by its own smell seems to
bring "assurance and relaxation" to the individual concerned.

In conjunction with scent, recent data suggest that vocalization may
play a key role in social interaction. In a fascinating paper to the
Journal of Mammalogy, Prof. David Macdonald, Paul Stewart and Josephine
Wong (WildCRU) describe a range of calls recorded during their
observation of the badger setts in Wytham Woods. The researchers
observed 16 calls: bark, chirp, chitter, churr, cluck, coo, growl,
grunt, hiss, kecker, purr, snarl, snort, squeak, wail and yelp. A full
description of the calls, along with audio files (.wav) and details of
when the calls are performed can be found on the
WildCRU website. In the
paper, Prof. Macdonald and his colleagues write that churrs, purrs and
keckers are restricted to adults; chirps, clucks, coos, squeaks and
wails to cubs; while the remaining eight calls (i.e. bark, chitter,
hiss, growl, grunt, snarl, snort and yelp) were exhibited by both. In
his 1975 opus Grzimek's Animal Life Encyclopedia (Volume 12, Mammals
III), the late German zoologist Bernhard Grzimek described a "piercing
scream" that is apparently emitted by wounded badger. Grzimek writes:

"This call [referring to a call reported during badger copulation]
resembles the death scream of a mortally wounded badger, a sound which
is so terrifying that many a hunter has ceased getting badgers after
hitting one and hearing the cry."

Despite the WildCRU biologists linking the acoustic
structure of the calls they witnessed to their function (which they
inferred from the context in which the call was made), they found no
evidence for either alarm calls to conspecifics or the long-range
'scream' to which Grzimek refers. Given the absence of loud (and thus
long-distance) calls, it is reasonable to assume that vocalization is
probably an inherently interpersonal form of communication that is used
on a strictly close-range basis (i.e. between individuals in close
quarters).

The promiscuity of badgers has long been suspected. There are
numerous reports of Eurasian boars being hounded by other males during
copulation, and a three year study of the Honey Badger (Mellivora
capensis) in the Kgalagadi
Transfrontier National Park in South Africa revealed a strict
hierarchical system in males with respect to female access. The dominant
boar had unrestricted access to the breeding sow; other subordinate
males were only seen to reach the female if the dominant badger had left
the sett to chase away another omega boar. Similarly, a recent paper to
the journal Molecular Ecology by a team of biologists from the
University of Sheffield, University of Leicester and the Central Science
Laboratory in York reports on the breeding biology of the badgers in Woodchester Park, Gloucestershire. The scientists found that males from
outside of the sow's social group -- typically boars from neighbouring
social groups – sired about half of the cubs to which they could
confidently assign paternity. Moreover, there were very few (ca. 22%)
successful matings between members of the same clan. These cases of
observed and inferred promiscuity undoubtedly serve to reduce the threat
of inbreeding. Indeed, a paper published in the Quarterly Review of
Biology recently suggests that the delayed implantation coupled with
superfetation may combine to help increase the reproductive fitness of
female badgers. Superfetation is the situation where two foetuses are
present in the uterus at the same time, but that have been fertilized at
different times. Despite claims that many animals exhibit superfetation,
verifiable cases are rare and the condition has only been well
documented in the group of freshwater fish called Mollies (Poeciliidae).
The authors of this study argue that this combination of features (the
superfetation and embryonic diapause) may make it difficult for dominant
boars to detect cubs that are sired by other males, promoting what the
biologists refer to as "cryptic polyandry". Not only does this cryptic
polyandry reduce the likelihood of inbreeding, but it may also reduce
the probability of infanticide -- dominant badgers are known to kill the
offspring of subordinates -- and increase the breeding sow's window of
reproductive opportunity by increasing her scope for conception. Indeed,
it is suspected that breeding sows may move between neighbouring setts
killing cubs in order to reduce the competition for food and give her
own a better chance of survival. More generally, infanticide could be a
means of saving costs associated with lactation and provisioning for
cubs, which would suggest that females in poor condition after breeding
might be more prone to infanticide than those in better condition.

Despite the common observation that many badgers remain within their
natal sett, some do disperse. A study on the well-established sett at
Woodchester Park in Gloucestershire found that badgers of all ages
permanently dispersed, with a tendency to move to smaller clans. Indeed,
the social groups were in a neigh-constant state of flux, with
immigrants from other setts that have died out, and emigration via
aggression and death through various means. Similar data from Wytham
Woods by Chris Newman and Christina Buesching show that about 50% of
badgers never disperse, while 30 to 40% undertake extended spurts of
dispersal (returning to the main sett after several weeks or months
absent) and 10 to 20% disperse permanently. The age of dispersing
individuals may be as young as seven or eight months and, although
dispersal this young is rare, a study on the Honey badger in South
Africa observed one female dispersing more than 50 km (31 mi) within
three weeks of independence! The peak period for dispersal in European
badgers is late June through to August. European badgers in the UK tend
to experience two distinct socially-unsettled periods: March to April
and August to September. The first of these periods is often because
cubs are killed while exploring their home range.

A study by Eloy Revilla and Francisco Palomares published in the
Journal of Animal Ecology found that prey type may influence dispersal,
as well as clan behaviour and structure. The researchers found that on
their study area in southwest Spain, badgers primarily ate rabbits and
territories were occupied by small clans consisting of a single
reproducing female and a reproducing adult male as well as some cubs
(the current and previous year's). Dispersal in these clans occurred
during the mating season of their third or fourth year of life. The
biologists also observed that territory use by these badgers varied
seasonally and between sexes. During the winter and spring, when food
was abundant in this area, the sows tended to stay close to the sett and
move very little, while during the summer -- when food was scarcer and
the sows had high energy demands owing to the raising of cubs -- they
covered the entire expanse of their territory looking for food. Boars
displayed a different pattern of movement. Male badgers covered a
roughly equal proportion of their territory during all seasons, but
moved faster, over greater distances and covered larger areas per period
of activity in the winter, when they were seeking mating opportunities
and defending their mates from interlopers (mate guarding). Indeed,
dominant boars were observed to form closer relations with dominant sows
than subordinate ones during periods of rest. (Back to Menu)

Interaction with Humans: In many areas, people share a similar
well-disposed attitude to badgers (more so than they do other urban
wildlife, such as foxes); some however, dislike the presence of badgers
on their property. Badgers are known to raid dustbins, and compost
heaps; they also dig up and eat bulbs and other crops – habits which
bring them into inevitable conflict with humans. Badgers are,
however,
protected under UK law, making it illegal to harm a badger or disturb
their setts. The primary legislation is the Protection of Badgers Act
(1992), which effectively consolidates all previous legislation, making
it an offence to: wilfully kill, injure or take, or attempt to kill,
injure or take a badger; possess a dead badger; cruelly ill-treat a
badger; dig for a badger; mark tag or ring a badger; or interfere with a
badger sett. The act brings a penalty of up to six months imprisonment
and a fine at Level 5 (up to £5,000, which is roughly US$ 9,130 or €
7,230). Schedule 6 of the Wildlife and Countryside Act (1981) prohibits
the use of certain methods of taking or killing a wild animal and the
Powers of Criminal Courts Act (1973) allows any property used to kill,
injure or take a badger (including dogs) to be seized. There are of
course exceptions to these rules and the Protection of Badgers Act
(1992) allows licences to be granted for research purposes and to permit
the intervention of local councils in the event of serious damage to
property. The same act also permits fox hunts to obstruct the entrances
of badger setts to prevent a fox going to ground, provided a strict set
of regulations are adhered to.

So, how effective is the legislation? The answer, it seems, depends
on the country in question and where the badgers choose to build their
setts. In a paper to Biological Conservation, two biologists from the
University of Belfast report on this subject. Linda Sadlier and Ian
Montgomery looked at the effect that protective legislation has had on
the badger population of Northern Ireland. Via a series of direct
observation and survey questionnaires, Sadier and Montgomery found that
not only was sett disturbance linked to clan size and number, but also
that Northern Ireland's badger population is being constrained by high
levels of sett disturbance. The authors consider that because most
badger setts are constructed on agricultural land (off the “beaten
track”), only landowners come across the badgers. Conversely, here in
Britain, public rights of access across most arable and forested lands
mean that destruction and/or disturbance to a badger sett is more likely
to be spotted and consequently reported to the police. For more
information on the legal aspects of badger protection, the National
Federation of Badger Groups (see Links) has provided a concise summary,
while the subject of badger baiting is covered briefly on the
Hunting
Wildlife page.

It is generally assumed that one of the main reasons some landowners
dislike badgers on their property is related to the loss of earnings
caused through consumption of crops. There are, however, little data
available to suggest how if this is much of a problem. A paper in
Mammal
Review in 2004 looked at badger populations in Luxembourg. In the paper,
the biologists report that during the period of 1995 to 1999, Luxembourg
farmers made an average of only 31 claims per year for crop damage by
badgers. This was found to be equivalent to an annual economic cost of
some €344 (£240 or US$435), which is negligible compared to the damage
caused by other large mammals (such as Wild boar, Sus scrofa).

Badgers can also be carriers of parasites that may be problematic for
humans and livestock. Lungworms (Metastrongylidae), hookworms
(Ancylostomatidae) and rabies (Rhabdoviridae) have been recorded from
badgers on the continent, while badgers in the UK are susceptible to a
range of lice (esp. Trichodectes melis), fleas (Paraceras melis), ticks
(Ixodes canisuga, I. ricinus, and I. hexagonus) and, in rare cases,
mange. In a paper to the journal Applied and Environmental Microbiology,
Sian Williams and colleagues at the University of Liverpool report the
presence of Salmonella enterica in the faeces of badgers from 18 social
groups in Chester, while Salmonella agama has been cultured from the
liver and faeces of a badger found dead on a farm in west England. These
bacteria, along with Salmonella binza, which has been isolated from a
badger latrine, are important pathogens for humans and livestock.
Badgers are also very susceptible to bacterial parasites and,
unfortunately for both themselves and most of Britain's cattle industry,
they appear to be highly effective vectors for Mycobacterium bovis,
which is responsible for causing tuberculosis in cattle (see: below and
Q/A).

Undoubtedly, one rather obvious human-badger interaction is road
death. Statistics for badger-road mortality (Road Traffic Accidents, or
RTAs) vary according to source, although most sources quote figures in
the region of 50,000, which probably stems from the figure of 15% RTA
mortality given by Ernest Neal and Chris Cheeseman in their book,
Badgers. Given the variation in number, size and use of roads across the
UK it is perhaps not surprising that there is considerable variation in
RTA mortality in Britain. According to the Isle of Wight Badger Group,
the number of badger road casualties has decreased slowly in recent
years, with 88 road deaths in 1997, 77 in 1998 and 76 in 1999.
Unfortunately, there are no reliable estimates of badger numbers on the
Isle of Wight, which makes getting an idea of the impact of roads on
this population difficult. Elsewhere, almost 70% of annual badger
mortality Woodchester Park was attributed to RTAs by one 1997 paper,
while nearly 50% of the annual losses observed at Wytham were the result
of collision with vehicles. On a more local scale, badger groups often
report that specific roads (and even specific stretches of roads within
their jurisdiction) can be hotspots for badger casualties. For example,
turning to page 13 of my local paper of 26th March 2004, the headline
read: "Badger 'graveyard' on district's roads". According to this brief
news piece in the West Sussex County Times, stretches of the Fittleworth
Road and the A29, as it cuts through Billingshurst, have seen unusually
high numbers of badgers involved in road traffic accidents. I find that
badger groups like to have road casualties reported to them. This way
they can keep an eye out for such hotspots and divert their attention
and funds to trying to reduce the impact on the badger population, often
by installing "Badger Reflectors" on established crossings. These are
small posts that reflect car headlights at the badger about to cross –
hopefully dissuading it!

While certain stretches of road can be significant areas of mortality
for badgers, the type of road can also make a difference. A recent paper
in Biological Conservation reports on the effects of roads on badger
mortality in southwest England. A team of biologists lead by Dr Philip
Clarke of York University analysed information on when and where
road-killed badgers were collected by MAFF (no DEFRA) during the
mid-1980s. Perhaps unsurprisingly, they found that there was a strong
seasonal skew in road deaths (more in spring) and that the number of
badgers killed was inversely related to how busy the roads were. For
example, the combined impact of motorways and dual carriageways
accounted for only 5.5% of all recorded badger road deaths, while Class
A and B roads accounted for almost 55%. Perhaps this reflects the
tendency for single carriageways to cut through countryside where
badgers are more likely to have established setts. The authors do point
out that laws preventing stopping on motorways might have affected the
data, leading to fewer carcasses being recovered. It should also be
remembered that traffic can also impose a significant barrier reducing
and even preventing dispersal – further work by the lead author suggests
that high traffic loads may discourage badgers from attempting to cross
motorways, dual carriage ways, Class A and Class B roads.

It seems that the predominant reasons for these road deaths are
two-fold. Firstly, grass verges on roadsides are kept short and are good
places to search for earthworms (probably explaining why road deaths are
highest during July when drought conditions often prevail) –
unfortunately the situation is compounded because badgers don’t tend to
run away from cars. Secondly, the high incidence of males dying on the
UK’s roads earlier in the year can probably be explained by these
individuals ranging more widely while searching for the last (and
generally younger) receptive sows. (Back to Menu)

Feeding Badgers (by Steph Powley)Often the best way to tempt
wildlife to linger in your garden long enough for you to get a decent
look is with the lure of food. Badgers will be attracted to foods such
as bread, nuts, peanut butter and dog food and in common with many
species of British wildlife they are very fond of custard cream
biscuits!

If you have spotted badgers feeding in, or passing through your
garden in the past, then it is best to place the food close to the path
they normally take, so that they are most likely to find it. If you are
unsure about whether badgers visit your garden, look for large holes in
your perimeter fences, paths worn through the lawn and small circular
holes in the grass appearing overnight, then place the food close to one
of these signs. To watch the badgers feeding from indoors, put the light
on in the room you wish to watch from when you put the food out at
around dusk, this way the badgers won’t be disturbed by movement and the
light will illuminate the area where they are feeding. Alternatively, if
your garden is well lit by streetlights, keep the lights in rooms
overlooking your garden off.

To watch them from outdoors, you will need to stay upwind of the
feeding site and remain very still and quiet throughout their visit
because badgers will be alert for the slightest movement while they are
eating. If you observe from outside, you will discover that badgers are
very noisy eaters! If you manage to attract badgers to feed in your
garden, you will find that they will come most nights and often stay for
up to 30 minutes. When more than one badger comes to feed in your
garden, you may witness squabbles between the animals, these seem to be
more about the social hierarchy of the clan than the need for food, as
such events occur even when food is plentiful.

Whatever wildlife you’re feeding, it is best to avoid feeding them
too much processed food, trying instead to include foodstuffs from their
natural diet. Chocolate should be avoided. (Back to Menu)